Pilot Debrief

Titan TITAN TORNADO S near Haskell, OK — 2020-05-09

Final reportCEN20LA173
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Date
2020-05-09
Location
Haskell, OK, USA
Airport
2K9
Aircraft
Titan TITAN TORNADO S
Registration
N318WH
Category
Airplane
Highest injury
Serious
Fatalities
0
Phase of flight
Climb

Probable cause

The student pilot/builder’s addition of winglets to the stabilator, which resulted in flutter and overstress failure of the stabilator control horn.

NTSB narrative

The student pilot departed on a flight in a kit-built airplane to test the winglets he had recently installed on the airplane’s stabilator, which were intended to eliminate the airplane’s uncommanded yaw. The flight was the airplane's first winglet test flight away from the airport traffic pattern and at a higher altitude. The student stated that during the flight, he decreased the pitch attitude to level off at 2,000 ft above ground level and the airplane suddenly vibrated aggressively and it "felt like the tail was thumping." He decreased the engine power, but the thumping and vibrating continued, so the pilot pitched the airplane down for an off-field emergency landing. Before he was able to land, the airplane rolled inverted and descended into the trees, resulting in the separation of the right wing. Postaccident examination revealed that the stabilator control horn had fractured due to overstress and separated from the push-pull tube. According to an airplane kit manufacturer engineer, winglets added to the stabilator produce flutter. Based on the evidence, it is likely that the winglets led the stabilator to flutter, which overstressed the stabilator control horn and resulted in the control horn’s failure.

Analysis

Primary failure mode
Mechanical failure
First missed decision gate
Pilot should have consulted manufacturer before modifying stabilator with winglets.

NTSB coding

Evidence available

  • Photos
  • 7 docket documents
View NTSB final reportView NTSB docket

Docket documents7

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